The present invention relates in general to tumbler wheel type changeable key operated locks having component structure similar to dial operated tumbler wheel combination locks, and more particularly to changeable combination key locks of the type having a plurality of peripherally gated tumbler wheels with hub portions selectively changeable relative to their peripheral gated portions, adapted to be conditioned upon manipulation of a key inserted therein to assume positions appropriate to the salients or bits of the particular key therein for setting the lock to the key configuration.
Conventionally, key locks usually employ pivoted lever tumblers or axially slideable pin tumblers to engage the contoured edge of the key blade or bit portion which adjust the lever tumblers or pin tumblers to positions releasing the lock to a condition so that the bolt can be retracted or moved to unlocking position. These key operated locks are usually of an entirely different construction and operation in accordance with different principles from conventional locks of the class known as tumbler wheel combination locks. Tumbler wheel combination locks usually comprise three or more tumbler wheels which are loosely journaled in coaxial, side-by-side spaced relation for rotation within a lock casing on a tubular arbor or post projecting inwardly from the front wall of the casing. The lock dial, which usually has 100 peripheral calibration marks thereon, is affixed to a dial spindle which extends through the bore of the tumbler post and has keyed to the inner end thereof a disc-like drive cam which is likewise arranged coaxially with and spaced rearwardly from the tumbler wheels. A drive pin projects forwardly from the drive cam and has a lost-motion connection through a conventional fly washer or ring with the rearmost tumbler wheel to drive the tumbler wheel in selected relation to the drive cam. A similar lost-motion connection is provided between each of the successive tumbler wheels so that each of the tumbler wheels may be driven upon predetermined rotation of the drive cam to position the peripheral notch or gate in each of the tumbler wheels in alignment with or facing a fence projecting laterally from a fence lever in overlying relation with the tumbler wheel peripheries to receive the fence in the aligned gates. The position of the fence in relation to the length of the fence lever nose is usually such that the fence is slightly spaced from the peripheries of the tumblers when the fence lever nose rides on the periphery of the drive cam.
Heretofore, a tumbler wheel type, changeable combination, key lock adapted for key operation, particularly for use with keys of the European type having bits or salients projecting from diametrically opposite portions of the shaft or stem of the key, has been proposed in earlier U.S. Pat. No. 3,991,596 assigned to the assignee of the present application, wherein tumbler wheels are supported for rotation about their common centers by convex arcuate peripheral wall segment supports guiding and supporting the outer diameters of the tumbler wheels. In such structure however, the friction torques arising from supporting of the tumbler wheels at their outer diameters is such that problems of jamming have occurred, preventing proper operation of the lock. Furthermore, in the structure disclosed in that prior patent, the fence lever was normally releasably latched in a raised inactive position and activated by a release spring and control cam structure to impact against a shoulder formation on the fence lever for releasing the fence lever from is latched condition and impelling it to a coupled relation with the drive cam at a particular angular position of the drive cam and when the fence lever gates were in aligned or facing relation to the fence. Improvement and simplification are desired in the structure for allowing the fence lever nose to only momentarily be accelerated toward the driving cam gate during rotation of the driving cam for coupling with the driving cam gate if the tumbler peripheries are properly aligned with the fence and to prevent fence lever nose coupling with the driving cam gate if the tumbler wheel gates are not properly disposed.
Also, it is an important object of the present invention to provide an arrangement for supporting a stack of tumbler wheels which cannot be supported at their centers, such as in the tumbler wheel key lock application, wherein the friction torque arising from the tumbler wheels is minimized so as to avoid jamming and similar defective operation, by constructing the tumbler wheel and interposing spacers between tumbler wheels in a manner to rotatably support the tumbler wheels at the perimeters of their hub portions rather than at the outer diameters of the outer rim portions of the tumbler wheels.
Other objects, advantages and capabilities of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings illustrating a preferred embodiment of the invention.